I've done some research in the intervening year, while my FS was converted to a single speed and later a five speed to give to a friend. I've put quite a few miles on it in the meantime.
Sears started selling Huffys as Free Spirits around '75, but they kept the Puch line until the early '80s. In '82 you could get the 10-speed Huffy for around $110, and the 10-speed Puch for $150. I have a 76-ish Huffy version, which has a small cult following because the construction makes it extremely comfortable for a road bike (A Huffy that doesn't suck? Amazing!) Puch bikes also got a step up in equipment all around.
All Puch Free Spirits have lugged construction, Huffys do not.
Sears licensed Ted Williams' name for their sporting goods in the '60s, and continued using it until the late '70s. The Williams name went on some Free Spirits. The red, white, and blue bicentennial bikes were sold in both Huffy and Puch versions. Puch-made Williams bikes have "Made in Austria" on the headbadge. Huffys have an identical headbadge minus this phrase.
Before Ted Williams, Sears sporting goods were named after department head J.C. Higgins, and pre-WWII bikes carried the Elgin name. Early-60's Higgins bikes were made by Puch.
I weighed my bike before the SS conversion at 39 lbs, and 34lbs. after. The old Shimano freewheel and chain are WAY heavier than modern components.